Democrats Back Off From Arms Curbs Opposed By President

WASHINGTON — Congressional negotiators reached an agreement Friday on arms control issues after House leaders backed off from major provisions that had been rejected by President Reagan.

In the compromise, the House dropped a proposal to mandate compliance with the unratified 1979 treaty on strategic arms limitations. The Democratic leaders of the House also dropped their proposed moratorium on nuclear tests while the president, from Reykjavik, Iceland, said he would take steps to move toward a comprehensive nuclear test ban treaty with the Russians.

The agreement was solidified with a telephone call between House Speaker Tip O'Neill and Reagan. ''I'm delighted that now we can go forward united,'' Reagan said in Iceland.

Although House leaders refused to say they had given in to the president, leaders have been worried this week about the political damage in this election year from appearing to ''tie the president's hands'' in his negotiations with Moscow. Since the Iceland meeting was announced the president has sharply criticized the House arms control provisions, saying they would undermine his negotiating efforts.

O'Neill, who this week said the president's attacks on House Democrats were purely political, acknowledged the bind the House Democrats were in and that they gave a lot more than they got.

''It falls short of a 50-50 arrangement,'' he said in announcing the agreement in the Capitol's Statuary Hall. ''There is a reason for that,'' he added. ''We in the Congress can legislate arms contol up to a point. We can use public statements in support of arms control, up to a point. But we cannot sit at the bargaining table in Iceland.''

On other arms control issues, the agreement cuts Reagan's funding request for his space-based missile defense shield by $1.8 billion, to $3.5 billion, about half way between the House and Senate approved levels.

The Senate and the White House agreed to the House-approved ban for fiscal 1987 on testing of anti-satellite weapons in space. The ban on testing was in effect last year. The House agreed to limited production of new chemical weapons with production of the 155-millimeter artillery shell. But the Senate and the White House agreed to the House ban on production of the main delivery vehicle for new binary chemical weapons, the Bigeye bomb.